Wireless body-area network time synchronization using R peak reference broadcasts

A method of fabricating a WBAN system for real-time telemonitoring health of a subject, comprising:

• providing a plurality of wearable biosignal sensors, each sensor of the plurality of sensors configured to measure a plurality of biosignals;
• providing a plurality of ultra-low-power radios correspondingly coupled with the plurality of sensors;
• providing a processor operable with at least one of the plurality of sensors and the plurality of radios,
• providing the plurality of ultra-low-power radios comprising configuring each radio of the plurality of ultra-low-power radios to receive the plurality of biosignals from each corresponding sensor and to transmit the plurality of biosignals to the processor via a WBAN, wherein providing a plurality of ultra-low-power radios comprises providing the WBAN as a single-hop network, wherein any device in the WBAN is capable of directly communicating with any other device in the WBAN, wherein providing the WBAN as the single-hop network comprises providing the device as an ECG sensor, wherein the plurality of biosignals comprises a plurality of ECG signals, the plurality of ECG signals providing ECG data;
• providing the processor comprising configuring the processor to:
• receive the plurality of biosignals from the plurality of radios, process the plurality of biosignals via a set of executable instructions storable in relation to a nontransitory memory device, the set of executable instructions comprising an instruction for synchronizing time of the plurality of biosignals by using the broadcasted R peak reference, whereby real-time health data is providable, and transmit the real-time health data to a healthcare provider,
• wherein providing the processor comprises configuring the processor to operate via one of:
• a first system architecture, wherein the ECG sensor is configured to transmit a short flag message every time that an R peak is detected, wherein the short flag message serves as a broadcast message to all devices, excluding the ECG sensor, in the WBAN, and wherein each receiving device records the time at which such device receives the short flag message;
• and
• a second architecture, wherein the ECG sensor is configured to transmit an entire ECG data stream, wherein the entire ECG data stream serves as a broadcast message to all devices, excluding the ECG sensor, in the WBAN, and wherein each receiving device is configured to perform an R peak detection on the entire ECG data stream and to determine a time at which each R peak occurs, wherein each R peak serves as a notable timestamp point for at least its distinct shape and facile identification, and wherein a set of times at which each R peak occurs defines ti.

A method of real-time telemonitoring health of a subject by way of a WBAN system, comprising:

• providing the WBAN system, comprising:
• providing a plurality of wearable biosignal sensors, each sensor of the plurality of sensors configured to measure a plurality of biosignals;
• providing a plurality of ultra-low-power radios correspondingly coupled with the plurality of sensors;
• and
• providing a processor operable with at least one of the plurality of sensors and the plurality of radios;
• providing the plurality of ultra-low-power radios comprising configuring each radio of the plurality of ultra-low-power radios to receive the plurality of biosignals from each corresponding sensor and to transmit the plurality of biosignals to the processor via a WBAN, and
• providing the processor comprising configuring the processor to:
• receive the plurality of biosignals from the plurality of radios, process the plurality of biosignals via a set of executable instructions storable in relation to a nontransitory memory device, the set of executable instructions comprising an instruction for synchronizing time of the plurality of biosignals by using the broadcasted R peak reference, whereby real-time health data is providable, and transmit the real-time health data to a healthcare provider;
• performing RBS using a broadcast message, corresponding to an R peak reference, to synchronize each receiver of a set of receivers with one another, whereby each node in the set of receivers is configured to receive the same broadcast message, and whereby each node in the set of receivers respectively experiences only nondeterministic latencies from only propagation time delay and receiving time delay, wherein performing RBS comprises:
• assuming that a set of receivers comprises two nodes, the two nodes comprising a first node and a second node, wherein tfirst node,A denotes a time that event A occurs with respect to a clock corresponding to the first node;
• broadcasting N distinct messages B to the first node and the second node via a transmitting node, wherein the first node and the second node respectively record a receive time for the N distinct messages B, and whereby respective timestamps tfirst node,B={tfirst node,B1, . . . , tfirst node,BN}T and tsecond node,B={tsecond node,B1, . . . , tsecond node,BN}T are generated;
• exchanging respective timestamps tfirst node,B={tfirst node,B1, . . . , tfirst node,BN}T and tsecond node,B={tsecond node,B1, . . . , tsecond node,BN}T between the first node and the second node;
• and
• performing a least-squares regression in relation to the node i, thereby determining a best linear fit for an expression y=mx+b, wherein y=tj−ti, x=ti, m=a clock skew, thereby determining a rate change of a difference in time between a node i clock and a node j clock, as measured in relation to the node i, and wherein b=a time difference between the node i clock and the node j clock at a time ti,B1, thereby enabling conversion of any timestamp from the node j clock to a timestamp which would have been generated by the node i clock, and thereby enabling conversion of any timestamp from the node i clock to a timestamp which would have been generated by the node j clock, whereby the two nodes of the set of receivers are synchronized with one another.

A method of real-time telemonitoring health of a subject by way of a WBAN system, comprising:

• providing the WBAN system, comprising:
• providing a plurality of wearable biosignal sensors, each sensor of the plurality of sensors configured to measure a plurality of biosignals;
• providing a plurality of ultra-low-power radios correspondingly coupled with the plurality of sensors;
• and
• providing a processor operable with at least one of the plurality of sensors and the plurality of radios;
• providing the plurality of ultra-low-power radios comprising configuring each radio of the plurality of ultra-low-power radios to receive the plurality of biosignals from each corresponding sensor and to transmit the plurality of biosignals to the processor via a WBAN, and
• providing the processor comprising configuring the processor to:
• receive the plurality of biosignals from the plurality of radios, process the plurality of biosignals via a set of executable instructions storable in relation to a nontransitory memory device, the set of executable instructions comprising an instruction for synchronizing time of the plurality of biosignals by using the broadcasted R peak reference, whereby real-time health data is providable, and transmit the real-time health data to a healthcare provider;
• performing RBS using a broadcast message, corresponding to an R peak reference, to synchronize each receiver of a set of receivers with one another, whereby each node in the set of receivers is configured to receive the same broadcast message, and whereby each node in the set of receivers respectively experiences only nondeterministic latencies from only propagation time delay and receiving time delay, wherein performing RBS comprises:
• assuming that a set of receivers comprises two nodes, the two nodes comprising a first node and a second node, wherein tfirst node,A denotes a time that event A occurs with respect to a clock corresponding to the first node;
• broadcasting N distinct messages B to the first node and the second node via a transmitting node, wherein the first node and the second node respectively record a receive time for the N distinct messages B, and whereby respective timestamps tfirst node,B={tfirst node,B1, . . . , tfirst node,BN}T and tsecond node,B={tsecond node,B1, . . . , tsecond node,BN}T are generated;
• exchanging respective timestamps tfirst node,B={tfirst node,B1, . . . , tfirst node,BN}T and tsecond node,B={tsecond node,B1, . . . , tsecond node,BN}T between the first node and the second node;
• and
• performing Deming regression in relation to a node i, thereby determining a best linear fit for an expression y=mx+b, wherein y=tj−ti, x=ti, m=a clock skew, thereby determining a rate change of a difference in time between a node i clock and a node j clock, as measured in relation to the node i, and wherein b=the time difference between the node i clock and the node j clock at the time ti,B1, thereby enabling conversion of any timestamp from the node j clock to a timestamp which would have been generated by the node i clock, and thereby enabling conversion of any timestamp from the node i clock to a timestamp which would have been generated by the node j clock, whereby the two nodes of the set of receivers are synchronized with one another.